U.S. Pat. No. 3,327,449, issued to Hullhorst and Lockett on June 27, 1967, discloses a machine wherein a stack of batts is mechanically compressed and vacuum is applied by a vacuum shoe along a longitudinal edge portion of the compressed stack. A paper sheet is wrapped around the stack and the vacuum shoe and the edges of the sheet are glued together over the vacuum shoe.
U.S. Pat. No. 3,382,643, issued to Hullhorst on May 14, 1968, discloses apparatus wherein a sidewall vacuum plenum of a compression station is used to move a stack of batts into the compression station from a loading station. A pressure plenum forming a lower platen of the compression station aids movement of a compressed stack by a cross ram into a bag.
U.S. Pat. No. 3,458,966, issued to Dunbar and Hullhorst on Aug. 5, 1969, discloses a method of pneumatically compressing fibrous batts by enclosing a stack in a plastic bag and evacuating air out of the bag endwise. A restraining sleeve is slipped over the bag and stack after they are compressed by ambient air pressure.
U.S. Pat. No. 3,499,261, issued to Hullhorst, Brown, and Mosier on Mar. 10, 1970, discloses three embodiments of packaging apparatus. FIGS. 1 and 2 disclose an open-top chamber into which a wrapping sheet and a stack of batts are placed. Endwall vacuum plenums evacuate air endwise out of the batts. A bottom wall pressure plenum ejects a wrapped stack. FIGS. 3 and 4 disclose means for compressing a stack of batts horizontally while a bottom wall vacuum plenum evacuates air transversely of the batts parallel to their major surfaces. FIGS. 5-10 disclose the apparatus of U.S. Pat. No. 3,382,643 mentioned above.
U.S. Pat. No. 3,824,759, issued to Finn and Smith on July 23, 1974, discloses apparatus wherein stacks of batts are partially compressed between sets of fingers at a loading station and then moved to a compression station having a sidewall vacuum plenum for holding the partially compressed stacks in the compression station while the loading fingers are withdrawn.
A problem with existing batt packaging machines and methods is that when longer batts, such as 8 foot batts, are used, they must be folded. This has traditionally been a labor intensive process. There is a need for an improved method and apparatus for automatically folding batts. Also, there is a need for such equipment to be flexible enough to enable rapid changeover and back from a mode in which the batts are folded to a mode in which the batts are unfolded.